Longus Capitis and Longus Colli

The most significant and common variations in prevertebral muscles concern the number of vertebrae to which the tendons of origin and insertion are attached. In addition, there may be fusion with the anterior scalene.

In about 4% of cases, a muscle (atlantobasilaris internus [Gruber] or axiobasilaris)extends along the medial border of longus capitis from the anterior tubercle of the atlas to the base of the skull.

Another muscle, epistropheobasilaris, is similar but arises from the second cervical vertebra. Atlanticomastoideus (Gruber) or rectus lateralis accessorius (Winslow)is a cylindrical, ribbon-like, or fusiform muscle extending from the transverse process of the atlas to the mastoid process.

The longus capitis is occasionally inseparable from longus colli.

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References

Anson, B.J., Ed. (1966) Morris' Human Anatomy,12th ed., The Blakiston Division, McGraw-Hill Book Company, New York.

Gruber, W. (1880) Über den Musculus atlantico-basilaris, M. epistropheobasilaris und andere von den obersten Halswirbeln zwischenden Mn. recti cappitis antici majores vorkommende Muskelvarietäten. Arch. Path. Anat. Physiol. Klin. Med. 82:465-473.